Introduction Ulnar shortening osteotomy (USO) is based on mechanical decompression of the ulnocarpal articulation by decreasing ulnar variance. The most commonly reported complications are plate irritation (up to 55%) and ulnar non-union (approximately 5%), both indications for reoperation. Only few studies report on predictors of complications, potentially leading to reoperation. The aim of this study was to identify factors associated with unplanned reoperation after USO. Secondarily, we aimed to determine the reoperation rate after USO and to report the types of surgery in reoperation.

Materials & Methods In this retrospective study, we included all patients older than 18 years of age who underwent ulnar shortening osteotomy at two level I trauma centers and one community hospital between January 2003 and December 2015. We used bivariate and multivariable analyses to identify factors associated with unplanned reoperation after ulnar shortening osteotomy.

Results Among 94 patients who underwent 98 ulnar shortening osteotomies, there were 34 unplanned reoperations (35%). Nineteen patients had removal of hardware (56%), 6 had a non-union osteotomy (18%). Patients who had an unplanned reoperation were more often affected at their dominant side (P=0.007), had a traumatic origin (P=0.003) and had prior surgery to the ipsilateral wrist (P=0.009). In multivariable analysis, factors independently associated with unplanned reoperation were the dominant side being affected (odds ratio 3.8) and traumatic origin (odds ratio 3.6).

Conclusion Ulnar shortening osteotomy is a technically demanding procedure which may lead to unplanned reoperations. Surgeons should be aware that one in three patients eventually may require an unplanned reoperation and incorporate predictive factors in their shared decision making.